In recent years, a lot of research has been done for a light emitting device which emits, as illumination light, fluorescence that a light emitting section including a fluorescent material generates in response to excitation light emitted onto the light emitting section by an excitation light source such as a semiconductor light emitting element, e.g., a light emitting diode (LED) or a semiconductor laser (LD: Laser Diode).
Examples of such a light emitting device encompass a vehicle headlamp disclosed in Patent Literature 1. The vehicle headlamp includes an LED module or an LD module as an excitation light source, and generates white light by emitting excitation light onto a fluorescent material formed into small dots each having a diameter of approximately 0.5 mm or less. The white light thus generated is reflected forward by a reflector having an elliptic spherical surface or a paraboloidal surface, so that the white light is incident on a projector lens.
Patent Literature 2 discloses a light source device including (i) a laser diode and (ii) a collimator, a condenser, and a fluorescent material each of which is provided ahead of the laser diode. A laser beam, which is coherent light, is transmitted through the collimator and the condenser, so that the condensed laser beam is incident on the fluorescent material. Consequently, the fluorescent material emits incoherent light.
Patent Literature 3 discloses that, in a case where an optical fiber cannot be provided at the vertex of a concave mirror, the optical fiber may be provided at a slant with respect to a center line extending from a focal point of the concave mirror to the vertex of the concave mirror.